7.2.Lexical conventions (Since 1.1.0)

• A script is a sequence of tokens separated by | or ||. Leading and trailing whitespace of every token is ignored; an empty token is skipped.
• The reserved characters are | ; ( ) { } [ ] # ! $ @ %. $ starts a native function, @ an expression marker, % a user-function call (§7.8); # separates a variation name; ! ends a gloss token; ; is the compound operator. A gloss name, expression name, or label MUST NOT contain | ; ( ) { } [ ], MUST NOT start with $, @ or %, and a gloss name MUST NOT end with !. A gloss name additionally MUST NOT contain % anywhere, and contains # at most once and never as its first or last character.
• There is no comment syntax and no escaping or quoting.
• Numbers are written as plain decimals (optional sign, digits, optional fraction). A producer MUST emit that form; a consumer MAY accept other numeric spellings. A non-numeric value in a numeric slot is an error.
• Arguments are positional and comma-separated inside one pair of parentheses, which MUST NOT nest. Every argument is optional: an empty or missing slot takes its default, and omitted parentheses mean all defaults. A trailing label slot takes the rest of the argument text, so a label may contain commas.
• Case. Gloss names, expression names (including none and break), user-function names, and anchor sites are matched case-insensitively. Native function keywords ($pause, $shift, $reset, $spell, $anchor, $mirror, $buoy, $compound, $viseme) are lowercase and case-sensitive.
• | splits only at bracket and brace depth 0, so the bodies of [ … ] and { … } keep their inner separators. ; splits only at parenthesis, bracket and brace depth 0.